The most important thing to know is that phone calls and text
messages have always been, and continue to be, intercept-able by
law enforcement through cooperation with wireless carriers. That
type of communication was not encrypted in April, and it's not
encrypted now. Further: Apple and Google have never been involved
in that legal process. If cops want to tap a bad guy's iPhone,
the cops have to go to AT&T or Verizon or whomever the bad
guys pay every month for data and voice.

The next thing to know is that, when it comes to Apple devices,
iMessage and Facetime have always been, and continue to be,
encrypted. Communication through those products was never
intercept-able by law enforcement — not back in April and not
now.

There has been one big change when it comes to iMessage, however.

Before Apple changed iOS, law enforcement would have been able to
get a warrant to break into a bad guy's phone and see if any
iMessages were stored on the device.

Today, after the rollout of iOS 8, the cops might not be able to
do that. That's because in iOS 8, stored iMessages are encrypted
— kept behind a password that only the owner of the phone knows.
The same goes for everything else stored on the device, including
emails and photos.

The only way the cops would be able to see saved iMessages,
photos, and other data the bad guys stored on their phones after
the rollout of iOS 8 would be if the bad guys backed up all that
data to iCloud OR to another device, like a laptop or desktop
computer. iCloud is not encrypted the way phones are, and all the
data is stored on Apple's servers. It can be accessed under
warrant. Likewise, most laptops or desktops don't have the
encryption that iOS 8 has.

When it comes to Google, the situation is basically the same:
intercepting phone calls and text messages has nothing to do with
Android encryption. Backed-up data on the device, however, is
less available to law enforcement now.